Replacement bolts/nuts should come with the new flex disc. Be sure to check the condition of the front flex disc too. You will need large open end wrenches to loosen the driveshaft coupling so the driveshaft will telescope to allow sufficient clearance for rear flex disc removal. If for some reason the driveshaft halves separate be sure to reassemble using the match marks or the driveshaft may be out-of-balance. It's likely that you will need to lower the exhaust system to work on the flex disc and driveshaft coupling. This is a DIY job, but time consuming ... at least when I did it.

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Fred Hoelzle